Why are drug induced hallucinations so compelling that they apparently provided much of the inspiration for early forms of abstract art? Researchers suggest that the answer hinges on an interplay between the mathematics of pattern formation and a mechanism that generates a sense of value and meaning.

Agreeing to pay £50,000 for something worth £2 wouldn't win you any haggling competitions. In mathematics, however, a similar result can bring you international acclaim. This is the case with recent progress towards the famous twin prime conjecture.

An "electric atomosphere" is not what you expect at a maths lecture. But it is what prevailed when Andrew Wiles announced his proof of a 350-year-old-old problem, Fermat's last theorem, exactly 20 years ago.